In early September, the first lady was interviewed by several of the major news networks. For the appearances, Mrs. O wore an Ann Taylor cobalt blue dress adorned with an Alexis Bittar elongated marquis pin. 
You can look like the first lady in a similar version of the dress, in black, available on, here. Wow, beautiful and down to earth!
For the interviews, thanks to
"Michelle Obama: It's Getting Better All the Time" [ABC News]
"Michelle Obama: President Is Not Going to Lose" [CBS News]